The following topics will be studied: (a) Tear Film (surface characteristics; analysis of components). (b) Corneal ulceration (collagenase in tears; inhibition of collagenase with alpha 2-macroglobulin; efficacy and toxicity of other inhibitors; morphology of ulceration; mechanism of stagnant epithelial defects). (c) Herpetic keratitis (efficacy, penetrance and toxicity of antivirals, especially adenine arabinoside and its derivatives). (d) Drug delivery (routes of penetration of drugs; efficacy of ocular insert devices). (e) Corneal wound healing (chemistry of scar collagen). (f) Corneal nutrition (metabolite and hexokinase levels in corneal epithelium in disease and during contact lens wear).